Application of cellulose derivatives



UNITED STATES rsrssrggoi-"rlcs amen-ion or cnwnoss nmva'rrvss f mum'nnamn.r..adrm% i in Drawing. so, 9; 7

This invention relates to compositions of tubes with the desired flexibility to penetrate body and! min] the ureter where the canal diotvaryingsiseahapeandiengthpartiallyor wholly composed of organic derivatives of celluis relatively small and more or less tortuand which may be constricted or even sublose. or pieces of cellulose derivatives. either solid or hollow, or circular, oval, elliptical. square. rec- ,stantially closed by means or abnormal or other tangular or other cross-sectional shape. and in condltions present therein.

beunderstoodas general, to surgical devices comprehended under the terms'upioratory and evacuative, as catheters. sounds or cannul'ae. being when solid, in-

tended tor distending a passage. and when hollow for insertion into a normal opening oithe body for injection or withdrawal of iiuids therein or therefrom and for medicamentation. or for.

insertion into an incision as in post-operative worhtordrainageandotherpurposes.

By theterm"catheter"ashereinapplied,isto thevariousslses. shapesandlengthsot (usually) hollowconltruc- Iilhe 'lhard" rubber catheters while they may be of the desired rigidity, are deficient in suppleness and *pliabllity. The comparatively large 10 amounts of sulturand suliur compounds con- 2m therein. together with the vulcanization wacceleraitoravmany ot which are nitrogen comvpoundsot pronounced toxicity. materially militate aiainst their .eilectiveness and narrow their range ol'saie applicability. hard rubber are prone to injure and wound delicate 1- membranes which are often extremely tender andsuseeptlhleduetoirritationsandinilamms- I tionrorintroductionoiasuhstanceintothebody -torycondltionsaothattheuseolthesecatheters throushanopeningorthewithdrawaloinmds zoismateriauylimited as scopeotappli theretromandreierredtoundertermssuchas "tionsndtothetechmqueandexperienceotthe anti-um. colonic. elbowed. double-elbowed, curved,

Eustachian. tsucial, female. in-dwelling, prostatic.

or winged catheters. tubes. inigators, and by Heretoiore, catheters have been made oi various materials showing adegreeoriiesibilltmas thinmetaltubing,rubberotvaiyingstaeesol vulcanization. and compounds .in the liquid or" semi-liquid condition built up over a web as of a isbrlc, usually by repeated dipp ng oi the same in manipulator. "Catheters are often used by the layman. sometimes daily. as in prostatic enlarge- L ment and analogous complications, and the unrielniinsorooertrohmiesuisedrubberolrreuini- T which. when continued, may and lead to serious chronic results.

on catheters, while usually of smoothfsuriace, have a-very low. elasticity and suppleness.

and there is always present the grave danger of breakage or chippin oil, especially where the iso! relatively extreme thinness. asis ,4 t mu .ror thisand other rasons.

:halolniion oi the coatins or impregnating mate- 7 catheters are harsh to delicate inem- 'the use of glass catheters involves an element oi innempmnetoirritateandwoundtissuesnpon dens r. n fl nthe a slimitedmd insertion. especially when the tissues are nitradeereasing'rangeoi'applicability. sensitive and unusually delicate, as in innam- --llnamel catheters, that is, catheters made of matoryand certain pathological processes and fglased porcelain. are used in a limited extent. v :normal and pathologic secretions exert a solvent They are prauically rig d with zero flexibility, "f l I elect on the metal which with some metals is 40 or relatively rough interior due to thediiiicultles very marked. Their-comparatively low elasticity e of interior glazing. and Very irasile in the thin wisalsoa- 'e tn ir gtensiv u l wall diameter as usually Prepared. By virvvtiiui. especially in urological work such asnrethof this .inherent rigidity. enamel catheters ral. ureteral and renal uploration and in eon- !or' adaptation to the varying oon- J nection with the removal of some forms oi renal 5 tour of the canslinto which they are intended .1 4 w ,=jmtobeinserted,andtheroughinteriorintroduces i m m of 17 rally in las the dangerotincomplete sterilization.

*tl y and suppleness dependent upon the degree 3 One of the objects of my invention is to overoi vulcanization to which the rubber has been come and minimise the herein enumerated and subjected. The soft rubber catheters arehighother disadvantages. w le still conservlns the .iy elasticbut more or less porous and spongy, 7' :points of dedraoility or these instruments as a li i d fllgulty insterillzation. and requiring as japplled tothe various uses'ior which such rigid sterilintion treatments as to matethey are normally intended, and Ihave found riallyshorten theirperiod o! eiiectiveness. ic! the inherent objections are overalso. inlgenerai. lack the requisite rigidity coucome etermaterlsiisjccm'poeedor juice, the bile acids, other secretions are'ofpfiznounced alkaline re- 4.

insoluble in water. The word "maximum" as especially where the degree "1'." pproaches the maximum.

By e ized cellulose as herein-used,is to be understood commercially alkylated,

aralky'lated ncrmalorm ce ose, as i h- W gai ures c e same as examples For many purposes and depending upon the physical properties desired in the finished cathel ter, and its size, dimensions, wall thickness, etc.. the desired elasticity, suppleness, flexibility. stability, and freedom from objectionable features for the plu'poses for which it is intended, I may of ce ulose ethers, mitten ona supp eness, Elasticity, etc., is desired, suitable plasticizers, flexilizers, softeners, extensiflers or su use a sin le or a cellulose ether or mixture l ning components 'r'fimcorpora "e ce ose e er m to impart the kind and degree of characteristics desired. The highly etherifled ethyl-celluloses and benzyl-celluloses e I' use n connec ion, on account of the number and amount of suitable plastifying components which may be harmoniously incorporated therewith to induce the specific properties required and the extent of the same desired.

The cellulose ethers, as a class, are insoluble in, and not detrimentally ailected by .herein used in connection with the etheriileation of cellulose or other carbohydrate, varies considerably in commercial processes, depending upon the nature of the etherifying process and the emciency of the particular apparatus employed in the various etherii'ying steps.

The available ethylcelluloses of commerce, insofar as is known to me, are not of maximum commercial degrees of ethylation. They are so ethylated as to meet most of the technical requirements for which they are intended. To prepare an ethylated cellulose of maximum etheriflcation is a relatively expensive operation, and not justifled by the usual requirements of this cellulose ether in the lacquer and plastics arts.

It is recognized that generally the water-insolubility, swelling-resistance in the presence of water or hydrous elements. and innocuousncss amount and of nature 20 alin, min. trypsin, olggpsi stegpsin. and oth foliy enzymes and fluids, the products elaborated in when" bladder, liver and kidney, both those that are normal to the healthy body and those formed under pathological conditions; they can be produced of a high degree of flexibility, and are not adversely affected by the usual antiseptics, disinfectants, bactericides. both cse o 'fiitilli'ifid honmetalffi fln. usually applied for sterilization purposes. As is well known. many of the normal or pathological body secretions either are distinctly acid in reaction as the hydrochloric acid in th e 0 ac an e like, w e

action. These chemically reactive mes often aided by enzymic action, exert an appreciable dissolving and decomposing efl'ect upon a catheter or instrument of analogous use, when made of rubber or a cellulose ester, especially where in 5 high degreeoila l lgyl a tign, are substantially insolec by chemical and other components elaborated by or in the human body in'health and disease.

This has been found to hold true to the maxlmum degree when ethylcellulose is the alkylcellulose employed, and where the ethylation has been allowed to proceed to commercially maximum etheriflcation.

duction of ethyl or ethoxy rest; to the extent 'of to of that theoretically possible, with the production of a cellulose ether substantially ibility. that is to say. where ethyla- 71 tion of the cellulose has resulted in the introreaction with chemical reagents,

to chemical reagents, gradually increases in proportion to the ethyl groups introduced into the cellulose aggregate, but heretofore no quantitative work has been done in determining the swelling, relative solubility and innocuousnes in normal and pathological fluids oi etbylcelluloses approaching the theoretical maximum in degree of ethylation. In the use of an ethylcellulose instrument of the catheter type, and in drainage after operations and for other purposes, especially in renal surgery and treatment for renal calculi, it often becomes necessary to allow the instrument to remain for days and sometimes weeks in contact with highly semitive membranes. In

such circumstances, it is of paramount importhey contact in normal use. This limitation of their use in this important fleld wherein heretofore they have been found unsatisfactory, has been overcome by me, by either ethylating cellulose with a theoretical excess of ethylating agent under optimum conditions. or by re-ethylating the usual commercial ethylcelluloses to substantially the maximum degree of etbylaticn.

Another valuable discovery made by me is that where the substantially maximum amount of ethyl groups are combined with the cellulose aggregate, it'is possible to add thermoplasticizers to the catheter substance so e softe g' point of the finished catheter or surgical instrument may be reduced to the temperature range of the lumen body." This advantage is manifested by the fact that the igidity of the catheter or other instrument maybe modified by insertion in the body, so that exploratory work, especially in connection with renal treatment and examiwnations, oi a nature which would be virtually impossible with a gid and non-thermoplastic body (as rubber) may be easily "Ihe cellul ethers as a body are characteriaed by relatively great stability and apathy to while still conserving an unusually high d gree of inherent flex- The cellulose ethers may be treated with lye solutions of high concentration with impunity, since there is no acid radical to saponify off ivy-alkaline treatment as is the case with the cellulose esters, and in addition are inert to many chemicals which injurimisly aiiect rubber and other materials of whichcatheters oi the present to 0.75 inch diameter. An antrum catheter usually has an exterior diameter range of 0.075 to 0.15 inch and a varying internal diameter. The exterior and interior diameters will, of course, be adjusted by the extrusion operation, taking into the consideration the amount, if any, of volatile solvent present and the relative volatility of the plasticizing portion added to the cellulose ether prior to the extrusion operation. The shape of the catheter tip may vary considerably, as in the olive, round or whistle tips, as examples.

In general, the substantially maximum ethylated celluloses have a relatively high inherent thermoplasticity, which property may be considerably augmented and varied in degree by the incorporation therewith of suitable known cellulose ether plasticirers and flexibility-inducing compounds, and still conserve the relatively high and permanent stability to, and insolubility in chemical reagents which characterize the cellulose ethers in general.

Likewise, it has been found that by the use of certain cellulose ether plasticizing and thermoplasticizing agents, stability of the etheriaed cellulose may be augmented, the porosity diminished, and the suppleness a'nd flexibility materially increased, without concomitantly decreasing otherwise valuable inherent characteristics.

There has been described a method of producing a catheter by first forming a textile core, dipping the core into a solution of cellulose or other compound, drying the same, then repeating the process until there has been built up on the textile center or core a sufilcient thickness of layers for the purposes intended. However,

such constructed tubes are porous. they have pinholes and blisters therein which increase the natural porosity, as compared with the cellulose ether composition of the nature as herein set stance. With a fabric core catheter built up in manner as above indicated, there is tendency upon use for the textile core to become frayed, and a fragment may be broken off and remain in the bladder or kidney, thus providing a nucleus or nidus around which a calculus may form.

Therefore, the catheter involved in this invention is of homogeneous structure throughout,

X-ray work or similar investigation, on account of variation of opacity.

At the close of the extrusion operation, the catheter may be dipped, sprayed, or otherwise coated with a cellulose compound in solution, and the instrument may be smoothed, polished, printed upon or otherwise treated to produce a finished appearing instrument. The printing operation may be conducted upon the extruded cellulose compound, either before or after the catheter is coated with a fluid compound, and either before or after the polishing or other flnishing operation.

What I claim is:

1. A tubular surgical device comprising a water-insoluble etherized cellulose of commercially maximum degree of etheriflcation.

2. A tubular surgical device comprising a neutral, water-insoluble alkylated cellulose of maximum alkylation.

3. A flexible, tubular surgical device of homogeneous structure, said device comprising a thermoplastic water-insoluble alkylcellulose of commercially maximum alkylation.

4. An instrument for withdrawal of fluids from the body comprising a water-insoluble alkylated cellulose of substantially maximum degree of alkylation.

5. A catheter comprising an ethylcellulose of substantially maximum degree of etbuvlation containing plasticlaer.

6. A catheter comprising a plasticized ethylated cellulose of commercially maximum degree of ethylation.

7.'A smooth catheter comprising a plasticizer and an ethylceilulose with an ethyl content of at least of that theoretically possible, said catheter being substantially insoluble in the fluids of the human body.

8. A catheter comprising a relatively long, hollow tube of small external diameter formed by extrusion from a thermoplastic mas of etherired cellulose so as to be externally smooth, continuous, non-porous and highly flexible but having sumcient inherent tensile strength and longitudinalrigiditytopermitinsertionbyitselfintoand through long, narrow and tortuous bodily passages, the degree of etherlflcation of said mass being so high as to render said catheter waterinsoluble and unaflected by moisture, substantially inert to bodily fluids and medicaments and to have the other inherent characteristics aforeand there is no dissimilar material core which said.

may break 01!, fray or cause an impediment in VINCENT JEROLCE FLYNN. 

